Terminals which are to be crimped onto cables each have an open-ended tube-like barrel which slips over the end of a cable in position for crimp fastening. The wall thickness of the barrel is critical and is commensurate with the strength and ductility of the material used for the barrel.
Such crimp terminals are offered in various gauge sizes (diameters) to accommodate various cable gauges. Crimping tools typically have crimping dies, that is, the portions engaging and deforming the crimp terminals, which can accommodate several different (usually 6-10) terminal barrel sizes. The dies, which usually come in facing pairs, are mounted on compound leveraged jaws and are brought together against opposite sides of the the barrel. This action crushes the crimp terminal against the cable, to secure the crimp terminal to the cable.
In crimping tools which are adjustable for barrels of different sizes, the crimping dies are adjustably connected to their respective jaws. The dies typically accommodate different barrel sizes by having different configurations (profiles of different sizes) along different portions of their edges. The orientation of a die in its respective jaw determines which portion of the die is facing the opposed jaw and die, and thus in position for crimping.
In prior crimping tools of this type, adjustable connection of such dies to their respective jaws has been accomplished in several different ways. Each of these ways has certain problems and disadvantages.
Some dies are loosely fitted into pockets on the jaws, such that they may either be readily removed and reinserted in a different orientation, or replaced with another die. This sort of adjustable die-in-jaw connection obviously involves loose dies, with the attendant problems of lost dies and sometimes time-consuming adjustment procedures.
A more favored adjustable connection utilizes as die members a pair of tool steel wheels with varying hexagonal or diamond-shaped die notches about their perimeters, such notches being sized to crimp terminals of specific gauge sizes. Each such die wheel is rotated on an axle mounted on its respective jaw in an orientation perpendicular to the plane of jaw motion. Such axle typically extends between a pair of parallel plates spaced from one another enough to accommodate the die wheel.
To crimp a certain size terminal, the die wheels on the two jaws are rotated until the notches of size appropriate for such terminal are in opposed positions, that is, are facing one another. The jaws are then opened so that the terminal can be placed between such opposed notches. Then the jaws are closed to cause the dies to crimp the terminal.
During such crimping action, die wheels have a tendency to rotate. If such die rotation is not restrained, the dies cannot be brought together squarely and defective crimps may result.
One device used to cage such die wheels includes, for each die wheel, a retractable pin member mounted to the jaw in a position which is offset from the axle on which the die wheel turns. Such retractable pin member is part of a rigid assembly which includes the axle on which the die wheel turns; the pin member is parallel to and radially offset from the axle. Such pin member is positioned to engage (slide into) a selected locating hole on the face of the die wheel and into an aligned hole or holes in the parallel plates which form the jaw.
Another device of the prior art for caging such die wheels has a retractable flat member which slides through slots in the jaw plates to engage the perimeter of the die wheel in a way making rotation impossible until disengagement of such flat member from the die wheel perimeter. These devices typically have springs biasing the retractable members toward their engaged positions.
These sorts of caging systems work well when everything is in alignment. However, these retractable pin and flat members have a definite tendency to bind, which can make disengagement and adjustment somewhat difficult. This problem is exacerbated by the misalignment which can occur from abuse, from high crimping pressures, and from ordinary wear. With either of these two systems for caging the die wheels, the sliding mechanism often fails to slide properly into position. And, the crimping pressure can bend or break the relatively fragile caging mechanism.
Still another drawback to such caging systems of the prior art is that they involve several parts, and because of this are rather expensive constructions. There is a clear need for an improved adjustable crimping tool.